cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A316147 Numbers, with digits in nondecreasing order, whose product of digits equals the number of digits times the sum of digits.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 36, 44, 159, 167, 235, 333, 1247, 1344, 2226, 11259, 11355, 111279, 111366, 112239, 112246, 112335, 1111377, 1111457, 1112337, 11111388, 11112267, 11113344, 11122236, 11222224, 111111399, 111111559, 111111666, 111112269
Offset: 1

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Author

David A. Corneth, Jun 25 2018

Keywords

Comments

This sequence can be used to find terms of A064154 by permuting digits of terms of this sequence.

Crossrefs

Cf. A064154.

Programs

  • Mathematica
    Union@ Flatten@ Reap[ Sow[0]; Do[ If[ FactorInteger[ nd s ][[-1, 1]] <= 7, Sow[ FromDigits /@ Reverse /@ Select[ IntegerPartitions[s, {nd}, Range[9]], Times @@ # == Length[#] Plus @@ # &]]], {nd, 18}, {s, 9 nd}]][[2, 1]] (* terms < 10^18, Giovanni Resta, Jul 18 2018 *)
    dnoQ[n_]:=Module[{idn=IntegerDigits[n]},Min[Differences[idn]]>=0 && Times@@idn==Length[idn]Total[idn]]; Select[Range[0, 111112300],dnoQ] (* Harvey P. Dale, Aug 12 2021 *)
  • PARI
    is(n) = my(d = digits(n)); vecsort(d) == d && prod(i=1, #d, d[i]) == #d * vecsum(d) \\ David A. Corneth, Jul 18 2018